Polyvinyl butyral is widely used in combination with one or more layers of glass to provide a composite which is resistant to shattering. The polyvinyl butyral typically contains a plasticizer to provide a balance of mechanical properties satisfactory for the subsequent handling and performance requirements. While many different plasticizers have previously been suggested for use in combination with polyvinyl butyral, continual effort has been directed to the discovery of plasticizers which combine outstanding performance characteristics, low cost and applicability to a wide range of glazing materials.